Speaker
Description
The discovery that superconducting qubits are sensitive to ionizing radiation has sparked interest beyond the quantum research community. Recent experiments, capable of detecting single interactions from cosmic muons and γ-rays, have highlighted the potential of these devices as a novel type of particle detector. As research in this field is still at an early stage and many questions remain unanswered, precious insights can come from the study of correlated errors, i.e. simultaneous state decays of multiple qubits on the same chip.
In this contribution we will present the new results achieved at the Gran Sasso National Laboratory (LNGS), Italy, where we measured correlated errors in two transmon qubits produced by a Ra-224 source. A Neutron Transmutation Doped (NTD) thermistor was glued on the same chip of the two qubits, allowing for the reconstruction of the spectrum of the deposited energy and the estimation of the detection efficiency of the two qubits. On the same chip was glued also a heater, i.e. a resistor, to study the response of the qubits to thermal phonons. A novel analysis strategy allowed us to identify radiation-induced events with a detection efficiency much higher than what obtained in previous studies, marking further progress towards the realization of a qubit-based particle detector.